Tips for dealing with snow on roofs

Friday

Feb 21, 2014 at 10:13 AMFeb 21, 2014 at 10:16 AM

Lancaster Fire Chief Mike Hanson issued the following press release about dealing with snow on your roof, in light of the rain expected:

The area has hit by several snow storms in the last few weeks leaving a large amount of snow build up on the roofs of homes and other buildings. With the addition of rain in the immediate forecast, dry, fluffy snow piled on roofs can act as a sponge, absorbing any additional moisture, adding weight and stress to structures if not cleared. The most danger occurs with flat, commercial roofs are most susceptible if they are not shoveled off or the roof drains are not working properly. In many cases, roof ice dams can form, causing water build-up, leading to interior damage.

The weight of the snow on a roof also varies, in turn varying the snow loading on the roof. A cubic foot of snow can weigh from seven pounds for snow that is new and dry to 30 pounds for old, compacted snow. Rain falling on accumulated snow will add more weight. Drifting snow can put excessive loads on the areas where it piles up, such as against equipment or penthouses, or at walls between roof levels.

To minimize the risk of over-stressing a building roof due to accumulated or drifting snow:

• Be on the alert for large accumulating snow build-up or snowdrifts on your roofs, particularly roofs that are flat or only have a slight pitch, as on garages, car ports or porches.

• If roof snow can be removed, from the ground, with the use of a snow rake (available at most hardware stores), do so. Use caution, as metal snow rakes conduct electricity if they come into contact with a power line.

• Try to avoid working from ladders, as ladder rungs tend to ice up. Snow and ice collect on boot soles, and metal ladders.

• Flat roofs can be shoveled clear, but only if it is determined that the roof is safe to stand upon. Exercise care when on the roof to avoid potentially dangerous falls.

• Flat roof drainage systems should be kept clear to minimize the risk of excess roof ponding in the event of subsequent heavy rainfall or melting.

• Large icicles can form on roof overhangs, but do not necessarily mean ice damming is occurring. Icicles overhanging doorways and walkways can be dangerous and should be carefully removed.

• All of the mentioned actions should only be performed by able-bodied adults, as the snow is heavy, and roofs and other surfaces may be slippery. Protective headgear and eye protection is recommended.